1. Technical Field
The present invention relates to the technical field of babies' products. More particularly, the present invention relates to a milk expressing device which can simulate a baby's suckling.
2. Description of Related Art
Studies show that the feelings of a lactating mother have a significant influence on her milk production. Some positive examples of such feelings are a mother's profound fondness of her newborn, the thought of her baby's cuteness, and the belief that her milk is best for the baby. All these positive feelings are conducive to the secretion of milk. Some physical sensations such as touching or seeing the baby or hearing the baby cry also contribute to the reflex of milk secretion.
Therefore, a mother needs to be alongside her baby all the time so as to be able to look attentively at, caress, and respond to the baby. Being in close proximity to the baby also prepares the mother's body for breastfeeding and facilitates lactation. If a mother is separated from her suckling baby between two consecutive breastfeeding sessions, milk secretion will be reduced.
Milk expressing devices on the market work typically on a single vacuum source which is configured for sucking at a human breast intermittently. This sucking action, though capable of milk expression, is totally different from a baby's suckling. Hence, when a mother has used such a milk expressing device for some time, the amount of expressed milk dwindles. Besides, in order to accelerate milk expression, the sucking pressure is often adjusted to an overly high level, which nevertheless causes pain.
U.S. Pat. No. 6,706,012B2 discloses a milk expressing device with two pressure sources (on the breast shields). While this device can massage the breasts to stimulate milk production, the nipples are deliberately excluded from the massaging areas such that the milk expressing action still differs from a baby's suckling action. Moreover, as a single pump is used as the source of pressure, the two pressure sources on the breast shields are linked in terms of control. This not only limits the variability of control over the breast shields but also makes it difficult to simulate the sensation of being suckled by a baby. In addition, the specifications of the single pump, which is in charge of both pressure sources, must comply with the one pressure source that has the higher flow rate requirement. As a result, the gas pump may be oversized for the other pressure source and prevents further reduction in volume of the device.
Another milk expressing device with multiple pressure sources (on the breast shields) is disclosed in U.S. Pat. No. 7,396,340B2. This device may be able to mimic a baby's suckling action to a certain degree but, owing to its complex structure and high production cost, is not suitable for mass production.